On 24.03.21 10:18, Andreas Schwab wrote:
On Mär 22 2021, Sean Anderson wrote:
int test_longjmp_ret(int i) { jmp_buf env; int ret; int foo = i;
ret = setjmp(env); if (ret) return foo; foo = 0x1000; longjmp(env, i); /* We should not arrive here */ return foo;This is undefined. When modifying a non-volatile auto variable between setjmp and longjmp, there is no requirement that the value is preserved.
Andreas.
Hello Andreas,
thank you for reviewing.
Your comment relates to the following paragraph in the C99 specification:
"All accessible objects have values, and all other components of the abstract machine have state, as of the time the longjmp function was called, except that the values of objects of automatic storage duration that are local to the function containing the invocation of the corresponding setjmp macro that do not have volatile-qualified type and have been changed between the setjmp invocation and longjmp call are indeterminate."
And foo is obviously "changed between the setjmp invocation and longjmp call".
The current version of the patch is: https://patchwork.ozlabs.org/project/uboot/patch/20210323181127.32411-3-xypr...
So I guess we have to declare env as volatile in setjmp() in this version of the patch because it is changed between the setjmp and longjmp invocations?
Best regards
Heinrich